The major objectives of this program are: 1) To refine for use in clinical laboratories, one or more nucleic-acid based techniques that will be feasible for the direct detection of blood-borne viruses in donors of organs for transplantation to reduce the antibody-negative window period between infectivity and detection to the shortest possible time, and when possible, obviate the need for indirect antibody tests; and 2) to file for Investigational New Drug exemptions (INDs) with the Food and Drug Administration (FDA), and submit and obtain approval for product license applications (PLAs). The major focus for this research is the earliest detection of infection by human immunodeficiency virus (HIV)1 including HIV-1, HIV-2, and HIV-0 a strain which is prevalent in Central Africa and which has recently been detected in the US. The assay should also have the flexibility to be readily adaptable to the detection of other variants of HIV that may emerge in the future. In addition, because of its clinical importance hepatitis C virus (HCV) must also be detected in a similar system. To improve practicality, the detection of more than one agent per test (multiplex system) is an important goal. The testing method(s) envisioned must be able to detect HIV and HCV, alone or in multiplexing format, but earlier availability of an individual test is more important than later availability of multiplexed assays. It is expected that the assay system(s) will be suitable for fool-proof performance at odd hours by less practiced staff.